If the PBoC is buying gold in excess of the amount that it offically reports, then logically it will not want these purchases to appear in import/export trade statistics. Like all central banks, the PBoC classifies and holds its gold reserves as “monetary gold” (i.e. “monetary gold is gold held as a reserve asset that is available to and controlled by monetary authorities”). Monetary gold is also exempt from reporting in international trade statistics / customs data. Therefore, like all central banks, the PBoC would not have to report any monetary gold that it purchased abroad and then imported into China.